摘要
The flysch of Maerzheng Formation in the Buqingshan Area is located in the southern margin of the East Kunlun region,and its main body contains a set of turbidite of deposition in the bathyal-abyssal environment.This paper studied the characteristics of sandstone of the flysch formation.The framework component of the Maerzheng Formation sandstones statistical results show that feldspathic litharenite,quartz,feldspar and lithic is 42%,37%,21%,respectively,and the provenance is mainly derived from recycled island arc and orogenic belt in category.The sandstones of Maerzheng Formation are characterized by SiO2values of 50.18%~74.05%(average value of 66.69%),CIA=43~69,∑REE values of 59.99×10-6~171.07×10-6,∑LREE/∑HREE=6.6~8.8;(La/Yb)N=6.6~10.7,(La/Sm)N=3.2~4.6,andδEu=0.59~1.04.The sandstone′s geochemical characteristic indicates that the flysch was formed in the tectonic setting of the active continental margin;the sandstone belongs to continental island arc type;the provenance is the volcanic-plutonic magmatic island arc orogene and metamorphic basement of northern East Kunlun block;the protolith of sandstone dominantly derived from felsic volcanic rocks,cogenetic plutonic and metamorphic rock of basement;the sedimentary basin is the ancient trench or fore-arc setting in the outside subduction complex.Consequently,it indirectly records the process of Buqingshan-A′nyemaqen Ocean from continuous expansion,to northward subduction,and finally to closure.